Do you like horses?

I find this to be one of the most puzzling a elusive catchphrases in the Fi=
resign canon.  It keeps showing up in various form in the background in var=
ious crowd scenes.

I BELIEVE it makes its first appearance on How Can You Be In Two Place At O=
nce When You're Not Anywhere At All.  I noticed it as "Do you like seahorse=
s?" Giant Rat of Sumatra.  It also shows up in the soap opera scene from In=
 the Next World You're On Your Own.  This is not necessarily an exhaustive =
list.  Can anybody cite other examples?

More importantly, does anybody know where it comes from originally?